Southbound – the southernmost record of Tylototriton (Amphibia, Caudata, Salamandridae) from the Central Highlands of Vietnam represents a new species

Abstract

A new species of the genus Tylototriton is described from Ngoc Linh Mountain, Kon Tum Province, in the Central Highlands of Vietnam based on integrative taxonomy, namely by combining molecular and morphological evidence. Tylototriton ngoclinhensis sp. nov. differs from all other congeners based on morphological data, allopatric distribution, and molecular divergence. In terms of genetic divergence, Tylototriton ngoclinhensis sp. nov. distinctly differs from the sister species T. panhai (6.77%) and from T. ngarsuensis (12.36%) based on the mitochondrial NADH dehydrogenase subunit 2 (ND2) gene. Tylototriton ngoclinhensis sp. nov. is a moderate sized and robust salamander species with large cephalic edges, parotoids, and vertebral ridge orange in coloration. The new taxon differs from its congeners by a combination of the following morphological characteristics: size medium (SVL 60.8–66.5 mm, TL 57.6–61.8 mm in males, and SVL 72.5–75.6 mm, TL 62.9–67.9 mm in females); head longer than wide; parotoids very prominent and enlarged, projecting backwards; tail length shorter than snout-vent length; vertebral ridge large, high and glandular in appearance; 14 large and distinct dorsolateral glandular warts; gular fold present; tips of fore and hind limbs overlapping when adpressed along the body; tips of fingers reaching between eye and nostril when foreleg is laid forward; dorsal surface and lateral sides of the head, upper and lower lips, dorsolateral glandular warts, vertebral ridge, the peripheral area of the cloaca and the ventral edge of the tail orange in coloration; the presence of a distinct black line extending from the posterior end of the eye towards the shoulder. Tylototriton ngoclinhensis sp. nov. is restricted to evergreen montane forests near water bodies on Ngoc Linh Mountain. We suggest that the new species should be classified as Endangered (EN) in the IUCN Red List. This new important discovery represents the eighth Tylototriton taxon described from Vietnam, and at the same time constitutes the southernmost distributional record for the whole genus in Asia.